Letters signed by Oliver Cromwell to the Governor of Warwick Castle, Colonel Joseph Hawkesworth MP, are among an archive of important Civil War and other historical documents to be auctioned at Bonhams' Printed Books, Maps and Manuscripts sale.
The auction takes place at New Bond Street on March 23.
On October 8, 1651, Cromwell, fresh from his victory over the future Charles II at the battle of Worcester, ordered Colonel Hawkesworth to reduce the size of the Warwick Castle garrison.
By the time of his second letter, in 1655, Cromwell had become Lord Protector of England and appointed Colonel Hawkesworth to captain of 100 volunteers.
The archive of Colonel Hawkesworth's papers has survived intact since the 17th Century and includes documents from key figures on both sides of the civil war.
In addition to the Cromwell letters, there are signed orders to Colonel Hawkesworth from Sir Thomas Fairfax, the commander in chief of the Parliamentary forces, to seize Warwick Castle, and a letter under the same signature appointing him Governor.
From the Royalist camp is a letter from Prince Rupert of the Rhine - signed simply "Rupert" - ordering the arrest of four Royalist soldiers accused of theft.
This item most probably came into Colonel Hawkesworth's possession as war booty.
Colonel Hawkesworth served as an MP in two of Cromwell's Parliaments and kept his position as Governor of Warwick Castle until 1660 when he was ordered to disband the garrison a month before the restoration the Monarchy.
He seems to have kept all the important correspondence relating to his command together with other significant official documents which he had acquired.
The sale will certainly be one to watch. Another bold ink signature signed by the Lord Protector, circa 1650, is currently on the market priced £4,950 ($8,200).